Abstract: The present invention relates to a process for the gas phase polymerisation of olefins, and, in particular, to a process for the gas phase polymerisation of olefins with recycle of fines to the reaction zone.

Abstract: The present invention relates to a polymer powder vessel, preferably a polymer powder storage and/or transport and/or degassing vessel.

Abstract: The present invention provides a process for the production of a degassed polymer powder, which process comprises a) feeding i) a principal monomer, and ii) one or more comonomers fed in an amount of at least 5000 ppmw relative to the principal monomer feed rate, and iii) optionally one or more added alkanes having 2 to 10 carbon atoms, fed in an amount of at least 1000 ppmw relative to the principal monomer feed rate; into a polymerisation reactor wherein the monomer and comonomers react to form a polymer comprising residual hydrocarbons comprising one or more hydrocarbons having 3 to 10 carbon atoms, and b) passing the polymer to a degassing step wherein it is contacted with a purge gas to remove at least some of the residual hydrocarbons, characterised in that: 1) the G/P ratio in the degassing step is higher than a minimum G/P ratio, G being the purge gas mass flow rate in the degassing step and P being the polymer throughput of the degassing step, and 2) the purge gas has a concentration of critical hydr

Abstract: The present invention relates to a method for controlling a process for polymerisation of an olefin, and in particular to a method for controlling a process for polymerising at least one olefin in a reaction zone, said process comprising in the reaction zone a reaction mixture and polymer particles, the reaction mixture comprising a principal olefin and at least one further reagent, and wherein the process is controlled using the ratio of at least one further reagent to principal olefin in the polymer particles in the reaction zone or in the amorphous phase of said polymer particles.

Abstract: The present invention relates to methods useful for the production of polymer powder, and in particular to a method for transitioning from a first process for production of a first polymer to a second process for the production of a second polymer during a polymerisation campaign in a polymerisation apparatus, said polymerisation apparatus comprising a reaction vessel and a degassing vessel, in which the respective first and second processes each comprise: (a) bringing a principal olefin and a comonomer into contact with a catalyst under gas phase polymerisation conditions in the reaction vessel to form the respective first or second polymer, wherein said first and second process utilise the same principal olefin but differ in at least one of (i) the comonomer used and (ii) the reaction temperature at which the polymer is produced, and (b) subsequently contacting the respective first or second polymer with a purge gas in the degassing vessel to remove unreacted monomers, characterised in that the method for t

Abstract: The present invention relates to a polymerisation process and in particular to a process for the copolymerisation of ethylene and an ?-olefin comonomer having 7 to 10 carbon atoms in a fluidised bed gas phase reactor in the presence of a multi-site Ziegler-Natta polymerisation catalyst characterised in that (i) said process is operated in condensed mode, (ii) the amount of said ?-olefin is maintained below that at which substantial condensation in the reactor occurs and (iii) at least one of the following apply: a) the catalyst has an uptake rate of 1-octene of at least 700; b) the polymerisation is performed in the presence of an activity promoter.

Abstract: The present invention relates to a nozzle for the injection of a liquid under pressure (3), comprising a vertical feed pipe (1) surmounted by a hollow head (3), the liquid under pressure being conducted between the outer wall (4) of the vertical feed pipe (1) and an inner tube (5), the upper part of the nozzle comprising at least one lateral orifice (6) for expelling the liquid under pressure (3).

Abstract: The present invention relates to a nozzle for the injection of a liquid under pressure (3), comprising a vertical feed pipe (1) surmounted by a hollow head (3), the liquid under pressure being conducted between the outer wall (4) of the vertical feed pipe (1) and an inner tube (5), the upper part of the nozzle comprising at least one lateral orifice (6) for expelling the liquid under pressure (3). This nozzle is characterized in that the upper end of the inner tube (5) of the vertical feed pipe (1) emerges at a height above the lateral orifice(s) (6), thereby making it possible, when stopping the injection of the liquid under pressure (3), to introduce a gas under pressure (8) via the inner tube (5) of the vertical feed pipe (1).

Abstract: Process for the introduction of liquid into a continuous process for the gas-phase polymerization of a olefin monomer and one or more other alpha-olefins in a fluidized-bed reactor, the liquid being introduced by at least one nozzle having a feed pipe and a sleeve sliding inside and at the end of the pipe, the position of the said sleeve along the feed pipe being determined by the pressure of the feed liquid and the return force of a preloaded spring, the spring having one end fixed to the sleeve and the other end to the feed pipe, the sleeve being provided with one or more recesses along its surface for sliding with the feed pipe, the recesses emerging in a groove around the circumference of the sleeve and below a circular stop integral with the same sleeve, the stop resting, when the nozzle is not in use, on a rim of the end of the feed pipe, the rim and the circular stop of the sleeve each being provided with a bearing surface, the contact area of which is minimized to allow good sealing.

Abstract: Process for the introduction of liquid into a continuous process for the gas-phase polymerisation of an olefin monomer and one or more other alpha-olefins in a fluidised-bed reactor, characterised in that the liquid is introduced by means of at least one nozzle comprising a feed pipe (1) and a sleeve (2) sliding inside and at the end of the said pipe, the position of the said sleeve along the feed pipe being determined by the pressure of the feed liquid (3) and the return force of a preloaded spring (4) the said spring having one end fixed to the sleeve and the other end to the feed pipe, the sleeve being provided with one or more recesses (10) along its surface for sliding with the feed pipe, the said recesses emerging in a groove (11) around the circumference of the sleeve and below a circular stop (8) integral with the same sleeve, the said stop resting, when the nozzle is not in use, on a rim (9) of the end of the feed pipe, the said rim and the circular stop of the sleeve each being provided with a beari